Control method and electrical regulator for a switching valve

The method involves rotating a switching flap (10) shaft (12) using an electric motor (18), and detecting the end position of the flap using a positioning device (22,26). A torque is applied to the switching flap shaft to hold the flap in the end position. An error is reported if it is detected that the switching flap shaft has rotated beyond the end position. Independent claims are included for a control method for installation preparation of a motor and positioning device; and for a switching flap actuator.